P0442

DTC P0442

SYSTEM DESCRIPTION
The DTC P0442 Evaporative Emission (EVAP) System Leak Detected diagnostic monitors the EVAP system for a small leak. The diagnostic runs when the ignition is in the OFF position, and the correct conditions are met . While the vehicle is operating, there are sources of heat transferred into the tank from the following:
- Exhaust heat
- Engine heat
- Ambient temperature

When the engine is stopped and the ignition is in the OFF position a change in the fuel tank vapor temperature occurs. This results in a change in the pressure of the fuel tank vapor space. This change in pressure is monitored by the control module , using the fuel tank pressure (FTP) sensor input. The EVAP diagnostic detects leaks as small as 0.51 mm (0.020 in). If the control module detects a change in the fuel tank vacuum/pressure less than a calibrated amount, this DTC sets.

DTC DESCRIPTOR
This diagnostic supports the following DTC.
DTC P0442 Evaporative Emissions (EVAP) System Small Leak Detected

CONDITIONS FOR RUNNING THE DTC

IMPORTANT: The following conditions must be met prior to ignition OFF.

- Before the PCM can report DTC P0442 failed, DTCs P0455, and P2199 must run and pass.
- DTCs P0107, P0108, P0117, P0118, P0452, P0453, P0496, P0498, P0499 , P1128, P1129, P2227, P2228, and P2229 are not set.
- A refueling event is not detected.
- The fuel volatility is not excessive.
- The ambient air temperature is 4°C (40°F) or above.
- The engine coolant temperature is more than 69°C (156°F).
- The fuel level is between 15 and 85 percent.
- The engine run time is more than 25 minutes.
- DTC P0442 runs once per drive cycle when the above conditions are met.

CONDITIONS FOR SETTING THE DTC
The control module detects a vacuum/pressure change that is less than the calibrated amount.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

DIAGNOSTIC AIDS
- To help locate an intermittent leak, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light. Introducing smoke in 15 second intervals will allow less pressure into the EVAP system. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
- To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT High Intensity White Light.
- For an intermittent condition, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-3:

Steps 4-5:

The numbers below refer to the step numbers on the diagnostic table.
3. Introducing smoke in 15 second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
4. This step verifies that repairs are complete and that no other condition is present.